Centroid Community CNC Support Forum

I have a tachometer like this.

So am I correct in thinking it should be the other way around? That way if the hz were set to 120 it would get the 3200 RPMs?

1) Is your VFD cable shielded and that shielding grounded at one end? How close is the VFD cable to other acorn cables or the controller itself? VFDs are notorious for generating noise.

2) If the motor is geared to the spindle at 26:59 then the motor would have to spin at about 7200rpm to achieve the 3200rpm spindle speed. That's about four times the rating on that motor and while possible it's not a good design.

The fact that the spindle is only 1600 when the motor is running at 120Hz is a sign that something is wrong. This is a three phase motor and you have it set for 4 poles- are you SURE that is correct? I would think it would have six poles.

3) don't worry about the braking until you get this sorted.

P.S. I have really no idea what I'm talking about.

1. That very well could be the problem because right now I have wires pretty much everywhere.

2. That was my thinking also. I'm going to have to EDM some new gears to fit. At 1710 I didn't know if it would be safe to go to a three to one? Granted, with me changing out the spindle bearings. Just wondering what that's going to do to my torque.

I'm just going off what the data plate on the motor says. Four poles

3. Noted, figured I'd get all that right before worrying about that too. Maybe it'll sort itself out.

P. S. neither do I!